#include "drm.h"

#if USE_DRM

#include <time.h>
#include <poll.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <inttypes.h>
#include <sys/types.h>

#include <libdrm/xf86drm.h>
#include <libdrm/drm_fourcc.h>
#include <libdrm/xf86drmMode.h>

#define DBG_TAG "drm"

#define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))

#define print(msg, ...)	fprintf(stderr, msg, ##__VA_ARGS__);
#define err(msg, ...)  print("error: " msg "\n", ##__VA_ARGS__)
#define info(msg, ...) print(msg "\n", ##__VA_ARGS__)
#define dbg(msg, ...)  {} //print(DBG_TAG ": " msg "\n", ##__VA_ARGS__)

struct drm_buffer {
    uint32_t handle;
    uint32_t pitch;
    uint32_t offset;
    unsigned long int size;
    uint8_t * map;
    uint32_t fb_handle;
};

struct drm_dev {
    int fd;
    uint32_t conn_id, enc_id, crtc_id, plane_id, crtc_idx;
    uint32_t width, height;
    uint32_t mmWidth, mmHeight;
    uint32_t fourcc;
    drmModeModeInfo mode;
    uint32_t blob_id;
    drmModeCrtc *saved_crtc;
    drmModeAtomicReq *req;
    drmEventContext drm_event_ctx;
    drmModePlane *plane;
    drmModeCrtc *crtc;
    drmModeConnector *conn;
    uint32_t count_plane_props;
    uint32_t count_crtc_props;
    uint32_t count_conn_props;
    drmModePropertyPtr plane_props[128];
    drmModePropertyPtr crtc_props[128];
    drmModePropertyPtr conn_props[128];
    struct drm_buffer drm_bufs[2]; /*DUMB buffers*/
    uint8_t active_drm_buf_idx; /*Double buffering handling*/
    lv_disp_draw_buf_t draw_buf;
} drm_dev;

static uint32_t get_plane_property_id(const char *name)
{
    uint32_t i;

    dbg("Find plane property: %s", name);

    for (i = 0; i < drm_dev.count_plane_props; ++i)
        if (!strcmp(drm_dev.plane_props[i]->name, name))
            return drm_dev.plane_props[i]->prop_id;

    dbg("Unknown plane property: %s", name);

    return 0;
}

static uint32_t get_crtc_property_id(const char *name)
{
    uint32_t i;

    dbg("Find crtc property: %s", name);

    for (i = 0; i < drm_dev.count_crtc_props; ++i)
        if (!strcmp(drm_dev.crtc_props[i]->name, name))
            return drm_dev.crtc_props[i]->prop_id;

    dbg("Unknown crtc property: %s", name);

    return 0;
}

static uint32_t get_conn_property_id(const char *name)
{
    uint32_t i;

    dbg("Find conn property: %s", name);

    for (i = 0; i < drm_dev.count_conn_props; ++i)
        if (!strcmp(drm_dev.conn_props[i]->name, name))
            return drm_dev.conn_props[i]->prop_id;

    dbg("Unknown conn property: %s", name);

    return 0;
}

static void page_flip_handler(int fd, unsigned int sequence, unsigned int tv_sec,
                unsigned int tv_usec, void *user_data)
{
    LV_UNUSED(fd);
    LV_UNUSED(sequence);
    LV_UNUSED(tv_sec);
    LV_UNUSED(tv_usec);
    LV_UNUSED(user_data);

    dbg("flip");

    if(drm_dev.req) {
        drmModeAtomicFree(drm_dev.req);
        drm_dev.req = NULL;
    }
}

static int drm_get_plane_props(void)
{
    uint32_t i;

    drmModeObjectPropertiesPtr props = drmModeObjectGetProperties(drm_dev.fd, drm_dev.plane_id,
                                    DRM_MODE_OBJECT_PLANE);
    if (!props) {
        err("drmModeObjectGetProperties failed");
        return -1;
    }
    dbg("Found %u plane props", props->count_props);
    drm_dev.count_plane_props = props->count_props;
    for (i = 0; i < props->count_props; i++) {
        drm_dev.plane_props[i] = drmModeGetProperty(drm_dev.fd, props->props[i]);
        dbg("Added plane prop %u:%s", drm_dev.plane_props[i]->prop_id, drm_dev.plane_props[i]->name);
    }
    drmModeFreeObjectProperties(props);

    return 0;
}

static int drm_get_crtc_props(void)
{
    uint32_t i;

    drmModeObjectPropertiesPtr props = drmModeObjectGetProperties(drm_dev.fd, drm_dev.crtc_id,
                                    DRM_MODE_OBJECT_CRTC);
    if (!props) {
        err("drmModeObjectGetProperties failed");
        return -1;
    }
    dbg("Found %u crtc props", props->count_props);
    drm_dev.count_crtc_props = props->count_props;
    for (i = 0; i < props->count_props; i++) {
        drm_dev.crtc_props[i] = drmModeGetProperty(drm_dev.fd, props->props[i]);
        dbg("Added crtc prop %u:%s", drm_dev.crtc_props[i]->prop_id, drm_dev.crtc_props[i]->name);
    }
    drmModeFreeObjectProperties(props);

    return 0;
}

static int drm_get_conn_props(void)
{
    uint32_t i;

    drmModeObjectPropertiesPtr props = drmModeObjectGetProperties(drm_dev.fd, drm_dev.conn_id,
                                    DRM_MODE_OBJECT_CONNECTOR);
    if (!props) {
        err("drmModeObjectGetProperties failed");
        return -1;
    }
    dbg("Found %u connector props", props->count_props);
    drm_dev.count_conn_props = props->count_props;
    for (i = 0; i < props->count_props; i++) {
        drm_dev.conn_props[i] = drmModeGetProperty(drm_dev.fd, props->props[i]);
        dbg("Added connector prop %u:%s", drm_dev.conn_props[i]->prop_id, drm_dev.conn_props[i]->name);
    }
    drmModeFreeObjectProperties(props);

    return 0;
}

static int drm_add_plane_property(const char *name, uint64_t value)
{
    int ret;
    uint32_t prop_id = get_plane_property_id(name);

    if (!prop_id) {
        err("Couldn't find plane prop %s", name);
        return -1;
    }

    ret = drmModeAtomicAddProperty(drm_dev.req, drm_dev.plane_id, get_plane_property_id(name), value);
    if (ret < 0) {
        err("drmModeAtomicAddProperty (%s:%" PRIu64 ") failed: %d", name, value, ret);
        return ret;
    }

    return 0;
}

static int drm_add_crtc_property(const char *name, uint64_t value)
{
    int ret;
    uint32_t prop_id = get_crtc_property_id(name);

    if (!prop_id) {
        err("Couldn't find crtc prop %s", name);
        return -1;
    }

    ret = drmModeAtomicAddProperty(drm_dev.req, drm_dev.crtc_id, get_crtc_property_id(name), value);
    if (ret < 0) {
        err("drmModeAtomicAddProperty (%s:%" PRIu64 ") failed: %d", name, value, ret);
        return ret;
    }

    return 0;
}

static int drm_add_conn_property(const char *name, uint64_t value)
{
    int ret;
    uint32_t prop_id = get_conn_property_id(name);

    if (!prop_id) {
        err("Couldn't find conn prop %s", name);
        return -1;
    }

    ret = drmModeAtomicAddProperty(drm_dev.req, drm_dev.conn_id, get_conn_property_id(name), value);
    if (ret < 0) {
        err("drmModeAtomicAddProperty (%s:%" PRIu64 ") failed: %d", name, value, ret);
        return ret;
    }

    return 0;
}

static int drm_dmabuf_set_plane(struct drm_buffer *buf)
{
    int ret;
    static int first = 1;
    uint32_t flags = DRM_MODE_PAGE_FLIP_EVENT | DRM_MODE_ATOMIC_NONBLOCK;

    drm_dev.req = drmModeAtomicAlloc();

    /* On first Atomic commit, do a modeset */
    if (first) {
        drm_add_conn_property("CRTC_ID", drm_dev.crtc_id);

        drm_add_crtc_property("MODE_ID", drm_dev.blob_id);
        drm_add_crtc_property("ACTIVE", 1);

        flags |= DRM_MODE_ATOMIC_ALLOW_MODESET;

        first = 0;
    }

    drm_add_plane_property("FB_ID", buf->fb_handle);
    drm_add_plane_property("CRTC_ID", drm_dev.crtc_id);
    drm_add_plane_property("SRC_X", 0);
    drm_add_plane_property("SRC_Y", 0);
    drm_add_plane_property("SRC_W", drm_dev.width << 16);
    drm_add_plane_property("SRC_H", drm_dev.height << 16);
    drm_add_plane_property("CRTC_X", 0);
    drm_add_plane_property("CRTC_Y", 0);
    drm_add_plane_property("CRTC_W", drm_dev.width);
    drm_add_plane_property("CRTC_H", drm_dev.height);

    ret = drmModeAtomicCommit(drm_dev.fd, drm_dev.req, flags, NULL);
    if (ret) {
        err("drmModeAtomicCommit failed: %s", strerror(errno));
        drmModeAtomicFree(drm_dev.req);
        return ret;
    }

    return 0;
}

static int find_plane(unsigned int fourcc, uint32_t *plane_id, uint32_t crtc_id, uint32_t crtc_idx)
{
    LV_UNUSED(crtc_id);
    drmModePlaneResPtr planes;
    drmModePlanePtr plane;
    unsigned int i;
    unsigned int j;
    int ret = 0;
    unsigned int format = fourcc;

    planes = drmModeGetPlaneResources(drm_dev.fd);
    if (!planes) {
        err("drmModeGetPlaneResources failed");
        return -1;
    }

    dbg("drm: found planes %u", planes->count_planes);

    for (i = 0; i < planes->count_planes; ++i) {
        plane = drmModeGetPlane(drm_dev.fd, planes->planes[i]);
        if (!plane) {
            err("drmModeGetPlane failed: %s", strerror(errno));
            break;
        }

        if (!(plane->possible_crtcs & (1 << crtc_idx))) {
            drmModeFreePlane(plane);
            continue;
        }

        for (j = 0; j < plane->count_formats; ++j) {
            if (plane->formats[j] == format)
                break;
        }

        if (j == plane->count_formats) {
            drmModeFreePlane(plane);
            continue;
        }

        *plane_id = plane->plane_id;
        drmModeFreePlane(plane);

        dbg("found plane %d", *plane_id);

        break;
    }

    if (i == planes->count_planes)
        ret = -1;

    drmModeFreePlaneResources(planes);

    return ret;
}

static int drm_find_connector(void)
{
    drmModeConnector *conn = NULL;
    drmModeEncoder *enc = NULL;
    drmModeRes *res;
    int i;

    if ((res = drmModeGetResources(drm_dev.fd)) == NULL) {
        err("drmModeGetResources() failed");
        return -1;
    }

    if (res->count_crtcs <= 0) {
        err("no Crtcs");
        goto free_res;
    }

    /* find all available connectors */
    for (i = 0; i < res->count_connectors; i++) {
        conn = drmModeGetConnector(drm_dev.fd, res->connectors[i]);
        if (!conn)
            continue;

#if DRM_CONNECTOR_ID >= 0
        if (conn->connector_id != DRM_CONNECTOR_ID) {
            drmModeFreeConnector(conn);
            continue;
        }
#endif

        if (conn->connection == DRM_MODE_CONNECTED) {
            dbg("drm: connector %d: connected", conn->connector_id);
        } else if (conn->connection == DRM_MODE_DISCONNECTED) {
            dbg("drm: connector %d: disconnected", conn->connector_id);
        } else if (conn->connection == DRM_MODE_UNKNOWNCONNECTION) {
            dbg("drm: connector %d: unknownconnection", conn->connector_id);
        } else {
            dbg("drm: connector %d: unknown", conn->connector_id);
        }

        if (conn->connection == DRM_MODE_CONNECTED && conn->count_modes > 0)
            break;

        drmModeFreeConnector(conn);
        conn = NULL;
    };

    if (!conn) {
        err("suitable connector not found");
        goto free_res;
    }

    drm_dev.conn_id = conn->connector_id;
    dbg("conn_id: %d", drm_dev.conn_id);
    drm_dev.mmWidth = conn->mmWidth;
    drm_dev.mmHeight = conn->mmHeight;

    lv_memcpy(&drm_dev.mode, &conn->modes[0], sizeof(drmModeModeInfo));

    if (drmModeCreatePropertyBlob(drm_dev.fd, &drm_dev.mode, sizeof(drm_dev.mode),
                    &drm_dev.blob_id)) {
        err("error creating mode blob");
        goto free_res;
    }

    drm_dev.width = conn->modes[0].hdisplay;
    drm_dev.height = conn->modes[0].vdisplay;

    for (i = 0 ; i < res->count_encoders; i++) {
        enc = drmModeGetEncoder(drm_dev.fd, res->encoders[i]);
        if (!enc)
            continue;

        dbg("enc%d enc_id %d conn enc_id %d", i, enc->encoder_id, conn->encoder_id);

        if (enc->encoder_id == conn->encoder_id)
            break;

        drmModeFreeEncoder(enc);
        enc = NULL;
    }

    if (enc) {
        drm_dev.enc_id = enc->encoder_id;
        dbg("enc_id: %d", drm_dev.enc_id);
        drm_dev.crtc_id = enc->crtc_id;
        dbg("crtc_id: %d", drm_dev.crtc_id);
        drmModeFreeEncoder(enc);
    } else {
        /* Encoder hasn't been associated yet, look it up */
        for (i = 0; i < conn->count_encoders; i++) {
            int crtc, crtc_id = -1;

            enc = drmModeGetEncoder(drm_dev.fd, conn->encoders[i]);
            if (!enc)
                continue;

            for (crtc = 0 ; crtc < res->count_crtcs; crtc++) {
                uint32_t crtc_mask = 1 << crtc;

                crtc_id = res->crtcs[crtc];

                dbg("enc_id %d crtc%d id %d mask %x possible %x", enc->encoder_id, crtc, crtc_id, crtc_mask, enc->possible_crtcs);

                if (enc->possible_crtcs & crtc_mask)
                    break;
            }

            if (crtc_id > 0) {
                drm_dev.enc_id = enc->encoder_id;
                dbg("enc_id: %d", drm_dev.enc_id);
                drm_dev.crtc_id = crtc_id;
                dbg("crtc_id: %d", drm_dev.crtc_id);
                break;
            }

            drmModeFreeEncoder(enc);
            enc = NULL;
        }

        if (!enc) {
            err("suitable encoder not found");
            goto free_res;
        }

        drmModeFreeEncoder(enc);
    }

    drm_dev.crtc_idx = UINT32_MAX;

    for (i = 0; i < res->count_crtcs; ++i) {
        if (drm_dev.crtc_id == res->crtcs[i]) {
            drm_dev.crtc_idx = i;
            break;
        }
    }

    if (drm_dev.crtc_idx == UINT32_MAX) {
        err("drm: CRTC not found");
        goto free_res;
    }

    dbg("crtc_idx: %d", drm_dev.crtc_idx);

    return 0;

free_res:
    drmModeFreeResources(res);

    return -1;
}

static int drm_open(const char *path)
{
    int fd, flags;
    uint64_t has_dumb;
    int ret;

    fd = open(path, O_RDWR);
    if (fd < 0) {
        err("cannot open \"%s\"", path);
        return -1;
    }

    /* set FD_CLOEXEC flag */
    if ((flags = fcntl(fd, F_GETFD)) < 0 ||
        fcntl(fd, F_SETFD, flags | FD_CLOEXEC) < 0) {
        err("fcntl FD_CLOEXEC failed");
        goto err;
    }

    /* check capability */
    ret = drmGetCap(fd, DRM_CAP_DUMB_BUFFER, &has_dumb);
    if (ret < 0 || has_dumb == 0) {
        err("drmGetCap DRM_CAP_DUMB_BUFFER failed or \"%s\" doesn't have dumb "
            "buffer", path);
        goto err;
    }

    return fd;
err:
    close(fd);
    return -1;
}

static int drm_setup(unsigned int fourcc)
{
    int ret;
    const char *device_path = NULL;

    device_path = getenv("DRM_CARD");
    if (!device_path)
        device_path = DRM_CARD;

    drm_dev.fd = drm_open(device_path);
    if (drm_dev.fd < 0)
        return -1;

    ret = drmSetClientCap(drm_dev.fd, DRM_CLIENT_CAP_ATOMIC, 1);
    if (ret) {
        err("No atomic modesetting support: %s", strerror(errno));
        goto err;
    }

    ret = drm_find_connector();
    if (ret) {
        err("available drm devices not found");
        goto err;
    }

    ret = find_plane(fourcc, &drm_dev.plane_id, drm_dev.crtc_id, drm_dev.crtc_idx);
    if (ret) {
        err("Cannot find plane");
        goto err;
    }

    drm_dev.plane = drmModeGetPlane(drm_dev.fd, drm_dev.plane_id);
    if (!drm_dev.plane) {
        err("Cannot get plane");
        goto err;
    }

    drm_dev.crtc = drmModeGetCrtc(drm_dev.fd, drm_dev.crtc_id);
    if (!drm_dev.crtc) {
        err("Cannot get crtc");
        goto err;
    }

    drm_dev.conn = drmModeGetConnector(drm_dev.fd, drm_dev.conn_id);
    if (!drm_dev.conn) {
        err("Cannot get connector");
        goto err;
    }

    ret = drm_get_plane_props();
    if (ret) {
        err("Cannot get plane props");
        goto err;
    }

    ret = drm_get_crtc_props();
    if (ret) {
        err("Cannot get crtc props");
        goto err;
    }

    ret = drm_get_conn_props();
    if (ret) {
        err("Cannot get connector props");
        goto err;
    }

    drm_dev.drm_event_ctx.version = DRM_EVENT_CONTEXT_VERSION;
    drm_dev.drm_event_ctx.page_flip_handler = page_flip_handler;
    drm_dev.fourcc = fourcc;

    info("drm: Found plane_id: %u connector_id: %d crtc_id: %d",
        drm_dev.plane_id, drm_dev.conn_id, drm_dev.crtc_id);

    info("drm: %dx%d (%dmm X% dmm) pixel format %c%c%c%c",
        drm_dev.width, drm_dev.height, drm_dev.mmWidth, drm_dev.mmHeight,
        (fourcc>>0)&0xff, (fourcc>>8)&0xff, (fourcc>>16)&0xff, (fourcc>>24)&0xff);

    return 0;

err:
    close(drm_dev.fd);
    return -1;
}

static int drm_allocate_dumb(struct drm_buffer *buf)
{
    struct drm_mode_create_dumb creq;
    struct drm_mode_map_dumb mreq;
    uint32_t handles[4] = {0}, pitches[4] = {0}, offsets[4] = {0};
    int ret;

    /* create dumb buffer */
    lv_memset(&creq, 0, sizeof(creq));
    creq.width = drm_dev.width;
    creq.height = drm_dev.height;
    creq.bpp = LV_COLOR_DEPTH;
    ret = drmIoctl(drm_dev.fd, DRM_IOCTL_MODE_CREATE_DUMB, &creq);
    if (ret < 0) {
        err("DRM_IOCTL_MODE_CREATE_DUMB fail");
        return -1;
    }

    buf->handle = creq.handle;
    buf->pitch = creq.pitch;
    buf->size = creq.size;

    /* prepare buffer for memory mapping */
    lv_memset(&mreq, 0, sizeof(mreq));
    mreq.handle = creq.handle;
    ret = drmIoctl(drm_dev.fd, DRM_IOCTL_MODE_MAP_DUMB, &mreq);
    if (ret) {
        err("DRM_IOCTL_MODE_MAP_DUMB fail");
        return -1;
    }

    buf->offset = mreq.offset;
    info("size %lu pitch %u offset %u", buf->size, buf->pitch, buf->offset);

    /* perform actual memory mapping */
    buf->map = mmap(0, creq.size, PROT_READ | PROT_WRITE, MAP_SHARED, drm_dev.fd, mreq.offset);
    if (buf->map == MAP_FAILED) {
        err("mmap fail");
        return -1;
    }

    /* clear the framebuffer to 0 (= full transparency in ARGB8888) */
    lv_memset(buf->map, 0, creq.size);

    /* create framebuffer object for the dumb-buffer */
    handles[0] = creq.handle;
    pitches[0] = creq.pitch;
    offsets[0] = 0;
    ret = drmModeAddFB2(drm_dev.fd, drm_dev.width, drm_dev.height, drm_dev.fourcc,
                handles, pitches, offsets, &buf->fb_handle, 0);
    if (ret) {
        err("drmModeAddFB fail");
        return -1;
    }

    return 0;
}

static int drm_setup_buffers(void)
{
    int ret;

    /*Allocate DUMB buffers*/
    ret = drm_allocate_dumb(&drm_dev.drm_bufs[0]);
    if (ret)
        return ret;

    ret = drm_allocate_dumb(&drm_dev.drm_bufs[1]);
    if (ret)
        return ret;

    return 0;
}

void drm_wait_vsync(lv_disp_drv_t * disp_drv)
{
    while(drm_dev.req) {
        struct pollfd pfd;
        pfd.fd = drm_dev.fd;
        pfd.events = POLLIN;

        int ret;
        do {
            ret = poll(&pfd, 1, -1);
        } while (ret == -1 && errno == EINTR);

        if(ret > 0)
            drmHandleEvent(drm_dev.fd, &drm_dev.drm_event_ctx);
        else {
            err("poll failed: %s", strerror(errno));
            return;
        }
    }

    lv_disp_flush_ready(disp_drv);
}

void drm_flush(lv_disp_drv_t * disp_drv, const lv_area_t * area, uint8_t * color_p)
{
    struct drm_buffer *fbuf = &drm_dev.drm_bufs[drm_dev.active_drm_buf_idx ^ 1];

    if(!disp_drv->direct_mode) {
        /*Backwards compatibility: Non-direct flush */
        uint32_t w = (area->x2 - area->x1) + 1;
        for (int y = 0, i = area->y1; i <= area->y2 ; ++i, ++y) {
            lv_memcpy(fbuf->map + (area->x1 * (LV_COLOR_SIZE / 8)) + (fbuf->pitch * i),
                    (uint8_t *)color_p + (w * (LV_COLOR_SIZE / 8) * y),
                    w * (LV_COLOR_SIZE / 8));
        }
    }

    if(lv_disp_flush_is_last(disp_drv)) {
        /*Request buffer swap*/
        if(drm_dmabuf_set_plane(fbuf)) {
            err("Flush fail");
            return;
        }
        else
            dbg("Flush done");

        drm_dev.active_drm_buf_idx ^= 1;
    }
}

#if LV_COLOR_DEPTH == 32
#define DRM_FOURCC DRM_FORMAT_XRGB8888
#elif LV_COLOR_DEPTH == 16
#define DRM_FOURCC DRM_FORMAT_RGB565
#else
#error LV_COLOR_DEPTH not supported
#endif

void drm_get_sizes(int32_t *width, int32_t *height, uint32_t *dpi)
{
    if (width)
        *width = drm_dev.width;

    if (height)
        *height = drm_dev.height;

    if (dpi && drm_dev.mmWidth)
        *dpi = DIV_ROUND_UP(drm_dev.width * 25400, drm_dev.mmWidth * 1000);
}

int drm_init(void)
{
    int ret;

    ret = drm_setup(DRM_FOURCC);
    if (ret) {
        close(drm_dev.fd);
        drm_dev.fd = -1;
        return -1;
    }

    ret = drm_setup_buffers();
    if (ret) {
        err("DRM buffer allocation failed");
        close(drm_dev.fd);
        drm_dev.fd = -1;
        return -1;
    }

    info("DRM subsystem and buffer mapped successfully");
    return 0;
}

int drm_disp_drv_init(lv_disp_drv_t * disp_drv)
{
    lv_disp_drv_init(disp_drv);

    int ret = drm_init();
    if(ret) return ret;

    lv_disp_draw_buf_init(&drm_dev.draw_buf, drm_dev.drm_bufs[1].map, drm_dev.drm_bufs[0].map, drm_dev.width * drm_dev.height);
    disp_drv->draw_buf = &drm_dev.draw_buf;
    disp_drv->direct_mode = true;
    disp_drv->hor_res = drm_dev.width;
    disp_drv->ver_res = drm_dev.height;
    disp_drv->flush_cb = drm_flush;
    disp_drv->wait_cb = drm_wait_vsync;
    return 0;
}

void drm_exit(void)
{
    close(drm_dev.fd);
    drm_dev.fd = -1;
}

#endif